The present invention relates to the art of construction and, more particularly, it relates to percussive action pneumatic devices for drilling holes in soils.
The invention can be utilized to utmost effectiveness for drilling holes in compactible soils.
At present, the practice of construction makes use of a variety of percussive action devices for drilling holes in soils.
A known percussive action pneumatic device comprises a cylindrical housing with a pointed head portion. The pointed end of the housing receives thereon a hollow cylindrical tip having a tail portion and a head portion. In most cases the tip has its head portion pointed, while the internal space of the tail portion has a conical or tapering surface adapted to engage about the housing. The diameter and length of the tip are selected to correspond to the diameter of the hole to be drilled.
Prior to a drilling operation, the selected tip is seated by its tapering surface onto the pointed head of the housing. Depending on the actual operating conditions, the pointed end of the tip is either placed against the soil surface or inserted into a previously dug hole. Then the percussive action pneumatic device is energized, and the hole is drilled. Upon the hole having been drilled, the percussive action pneumatic device is withdrawn therefrom. However, when either a vertical or a blind horizontal hole has been drilled, the tip remains in the hole, since it is practically impossible to withdraw it therefrom.
A disadvantage of the known device is this impossibility of recovering tips from blind holes, which significantly raises the cost of drilling holes.